Within a wireless network, one or more stations (STAs) may communicate with an access point (AP). Some STAs may include high performing STAs such as laptops, etc, which are less constrained by battery life, and smaller battery powered STAs such as for example sensors, which may need to last many years on limited battery capacity. STAs typically enter a power save (PS) mode when not needing to transmit or receive frames. The PS mode is especially important for the STAs with smaller batteries.
Legacy STAs, however, must wake up from PS mode at scheduled time intervals known as Delivery Traffic Indication Message (DTIM) intervals, to listen for beacons from an AP to determine if any group-addressed frames, which have been buffered by the AP, are available to be received. Waking up at DTIM intervals, which can be as short as 200-400 milliseconds (ms), can adversely impact the STA's battery life. More advanced, power saving, STAs have the capability to wake up from PS mode on their own schedule, which may be significantly longer than a DTIM interval, to send a trigger to the AP. The trigger signals to the AP that the STA is ready to receive any available group-addressed frames, which have been buffered by the AP. This power saving may greatly extend battery life of the STA.
A problem arises, however, in that duplicate group-addressed frames may be received by the STAs since these group-addressed frames may be transmitted multiple times, for example, in response to triggers from power saving STAs and at DTIM intervals for legacy STAs. If a legacy STA happens to be awake while a group-addressed frame is being transmitted in response to a trigger from a power saving STA, the legacy STA will receive duplicate frames. Similarly, if a power saving STA happens to be awake during a DTIM interval it will receive duplicate frames.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art.